This disclosure relates to airfoils, such as those used for blades or propellers, that utilize protective sheaths to reduce damage from impact of objects striking the airfoils.
Airfoils are typically designed to meet desired requirements for the impact of foreign objects. For instance, propeller and fan blades may be designed to meet regulations for a bird strike.
The design requirements may be especially challenging for airfoils constructed of composite materials that may be less ductile than airfoils formed of metallic alloys. In some cases, the airfoils may include a nickel sheath for better resistance to erosion. However, this material is relatively brittle and does not absorb much energy in a foreign object impact. Additionally, known sheaths are difficult or expensive to manufacture with the desired coverage and properties for airfoil designs that have a relatively wide chord length.